The gradients used in magnetic resonance imaging (MRI) systems generate eddy currents. The eddy currents change the phase of each pixel in an unknown manner. Therefore, when phase differences are measured, such as in certain flow sequences, there is no way of knowing how much of the phase differences are due to flow and how much are due to eddy currents.
Some scan sequences use gradients of a first polarity followed by gradients of an opposite polarity as part of the sequence to quantify flow for example. The gradients each produce eddy currents that are not necessarily matched and hence not cancelled by subtraction methods. Accordingly, in such scan sequences the phase differences due to eddy currents cause erroneous flow measurements.
Accordingly, those skilled in the art have been and are still attempting to develop systems and/or methods to correct for eddy current caused phase angle degradation.